NYC-WTC_000199238

NYC 9/11 Public Portal Document

104 East 25th St, 10th Floo New York, New York lOOK '/vww.atc-enviro.con 212.353.828( Fax 212.353.830f ASSOCIATES INC.

April 29, 2002

Mr. Bernard P. Orlan Director, Environmental Health & Safety New York City Board of Education 28-11 Queens Plaza North Long Island City, NY 11101-4008

Re: Respirable Particulate Monitoring Various School Locations ATC Project No. 15-19125-0314

Dear Mr. Orlan:

ATC Associates Inc. (ATC) is pleased to provide this report of the results of real­ time air monitoring of respirable particulates conducted on April 26, 2002, at numerous locations. The New York City Board of Education (BOE) requested this monitoring to obtain comparison data for lower Manhattan schools.

SCOPE OF WORK

Sonny Ramlal, Environmental Technician from ATC’s .New York City office, conducted the monitoring. ATC’s findings are based on real-time environmental measurements. Real-time readings of respirable particulates PM2.5) were collected from outdoors and limited indoor locations.

ATC recorded concentrations of respirable particulates with a Dust Trak® Aerosol Monitor Model 8520, manufactured by TSI, Inc.

The assessment was performed consistent with generally accepted air quality assessment practices. As with all such assessments, there were inherent limitations created by constraints of time, operational and work practice variability, variations in air quality parameters, and sampling and analytical accuracy. The results of the sampling represent conditions found on the date of the survey and may not represent conditions found at other times.

EVALUATION CRITERIA

The target guidelines for the parameter that ATC evaluated during this investigation are shown in the following table.

CITY_21MC100_003048107

NYC-WTC_000199238